The son of producer/screenwriter Robert Presnell, Robert Presnell Jr. also became a screenwriter after working as a reporter in Milwaukee. From there, he worked in the New York radio scene as a producer, director, and writer. Presnell also published a few short stories. In the mid-'40s, he moved to Los Angeles and worked on radio with Orson Welles and on the "I Love a Mystery" series. From there he began writing screenplays and teleplays during the '50s and '60s. At one time, Presnell served on the board of directors and with the arbitration committee for the Writers Guild of America/West.